Could a drug used to treat a minor condition like pinworms help fight pleural mesothelioma someday? Researchers at Johns Hopkins University think so. The repurposing of drugs in oncology (ReDO) movement has made great strides in recent years, with researchers discovering that a large number of “old” drugs intended to treat relatively minor conditions could also possess remarkable anti-cancer properties. One such drug is mebendazole.

Also known as “MBZ,” mebendazole is a broad-spectrum benzimidazole anthelmintic drug in the same class as flubendazole, albendazole, oxfendazole, and others. The drug has been used for more than 40 years to treat a range of parasitical worm infections including threadworm (pinworm), tapeworms, roundworms, and other nematode and trematode infections. The drug has been successful in treating parasitic conditions in both humans and domestic animals.

In 2014, researchers found in a broad range of pre-clinical studies across a number of different cancer types that MBZ has anti-cancer properties. Several case reports of anti-cancer activity in humans were noted and data suggested that mebendazole would synergize with a range of other drugs, including existing chemotherapeutics. Candidate cancer types cited for further study included melanoma, non-small cell lung cancer, adrenocortical cancer, colon cancer, breast cancer, leukemia, and osteosarcoma.

Fast forward to today. A report released by NPR.org explains how Johns Hopkins researchers discovered that after treating lab animals for pinworm with MBZ, the drug not only staved off the parasites, it stopped cancer from developing in the mice that had been implanted with cancer cells. Other researchers were already testing the drug and its effects on lung cancer and melanoma. Phase I studies showed that the drug was well tolerated in children and adults. This was not surprising, since MBZ has been used for decades around the world to treat worm infections.

Researchers at Johns Hopkins hope to begin Phase II trials soon to further study the effects of the drug in adult cancer patients—beginning with brain cancer. The hope is that MBZ will have the ability to help the body manage all types of cancer, including mesothelioma, in combination with other repurposed drugs.

Per the U.S. National Library of Medicine (NLM) of the National Institutes of Health (NIH), Teva Pharmaceuticals ceased production of MBZ at the end of 2011. However, the drug retained FDA approval and continued to be sold under several generic names. In 2013, Amedra Pharmaceuticals bought the marketing rights to MBZ and Teva, and costs for the drug began to soar. Now available under the brand name Emverm, MBZ costs $367 for a 100 mg tablet in the U.S. That’s an incredible leap from just $4.50 before Amedra acquired marketing rights.

Though prices skyrocketed before interest rose in MBZ as a potential cancer treatment, a successful Phase II trial could push costs even higher. Researchers are also seeking ways to lower the costs of potential cancer drugs such as MBZ.